EVIDENCE
Methods
A source-based note, an external measurement and an original measurement are different kinds of evidence.
A claim should carry enough context to check it. These notes distinguish what a document says, what a calculation assumes, and what an experiment actually measured.
Four kinds of evidence
| Label | Meaning |
|---|---|
| Source-based note | An explanation of identified publications and their limits |
| Calculated example | Arithmetic with stated assumptions; no experiment implied |
| External measurement | A result attributed to its original author, sample and conditions |
| Original measurement | A documented experiment by this publication; none is included on these pages |
What these notes cover
These notes start with instrument credibility: a title is not a sensor; true carbon dioxide is not eCO₂; particles are not gases; low-cost TVOC and HCHO stay relative. Ventilation notes quote HSE placement and the 1500 ppm ventilation action line, RevK’s published climbs, and the 400 ppm ABC assumption. Particle notes explain how to log cooking and a window. Formaldehyde and TVOC pages stop at limits. Consumer readings are not a medical result and are not written as a known health risk.
What a documented room test needs
A result presented as an original measurement needs the instrument identity and firmware, the named sensor type, placement distances, occupancy, window and hob state, whether ABC was on, timezone as printed, the raw CSV, and a sentence that states the limits. An empty results column is not a pass. An original carbon-dioxide conclusion would also need a true NDIR or photoacoustic instrument and a multi-day occupied series. An original mass-concentration page would need a reference particle instrument. Those files are not on this site.
A blank record
The download contains column headings and one empty row, without fabricated sample readings. It is a documentation aid, not a test procedure and not a certificate.
Download blank air-quality event record ↓How sources are chosen
These notes prioritise identifiable original work and official documents. Author sites that are not manufacturers, manufacturer research posts, component tutorials and shop listings serve different purposes. A shop catalogue sentence can name a model; it does not establish a handbook specification.
The notes cited here include HSE’s workplace carbon-dioxide page; RevK’s 2019–2022 British house logs; Jeff Geerling’s 2021 and 2025 home-office notes; Tyler Cipriani’s cooking-aligned particle chart; Yoctopuce’s ABC calibration article; Adafruit’s SCD-30 and SCD-4x tutorials; and AirGradient’s manufacturer posts on photoacoustic versus NDIR and on SGP41. Manufacturer and vendor pages are labelled as such. Their work is attributed rather than presented as an AirMeasure UK result.
Review, revisions and corrections
These notes are attributed to AirMeasure UK. They are not a review by a named occupational hygienist, a ventilation engineer or an accredited laboratory. If a named person reviews a page, that person and the scope of the review will be identified.
The date on a page marks when the text or sources were last checked. It does not mean a room was logged that day. Corrections identify the changed claim and its basis. Corrections with the page, passage and source.
Commercial relationships
The operator also owns instrument retail sites. Related retail names stay on the commercial disclosure. Ownership never substitutes for testing. These notes do not use those shops as a buying guide.
Policy text reviewed 23 September 2026.